1 July 2012 draft, submitted to Competing Motivations, ed. by Edith Moravcsik and Andrej Malchukov, Oxford University Press Please do not cite without permission. Comments welcome and appreciated! Why move? How weight and discourse factors combine to predict relative clause extraposition in English Elaine J. Francis Purdue University Laura A. Michaelis University of Colorado at Boulder Abstract In relative clause extraposition (RCE) in English, a subject-modifying relative clause is displaced to a position following the verb phrase, as in Some research was conducted that supports the existing theory. Previous studies have revealed that both grammatical weight (i.e. relative constituent length) and discourse factors are important for determining when and why speakers use RCE. However, the current study is the first to examine the interaction of these factors. A quantitative analysis of RCE and comparable non-RCE tokens in the International Corpus of English Great Britain (ICE-GB) showed a strong effect of grammatical weight: there was a strong preference for RCE when the relative clause was at least five times longer than the verb phrase, and a strong preference for canonical (non-RCE) order when the relative clause was the same length or shorter than the verb phrase. However, for those tokens with length ratios falling